Move to a more efficient pid-table impl. Note that the

change in common_init() will mean that mod_ssl won't cleanly
patch, so before we release, we'll need to make sure they
are aware.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@588214 13f79535-47bb-0310-9956-ffa450edef68